Homicide Squad detectives are appealing for public assistance following the disappearance of South Australian man Kerry Giakoumis.
The 29-year-old Adelaide man travelled to Melbourne on 5 June with two associates who police believe are members of the Hells Angels Outlaw Motorcycle Gang.
It's not known why Kerry came to Victoria, however he had told family that he intended to work here as a concreter.
Whilst in Melbourne, Kerry regularly spoke with his family in South Australia and his mother had booked a flight for Wednesday, 10 June for him to return home on.
Kerry didn't board the flight and contact with his family ceased.
They subsequently reported him missing to police, and his disappearance is being treated as suspicious.
Police believe Kerry attended the Hells Angels clubhouse on Lipton Drive, Thomastown with Hells Angels and other associates in the early hours of 10 June.
This is the last time police have information of Kerry being seen.
Detectives are keen to speak to anyone who has information about what happened at the clubhouse or any other location in the early hours of 10 June.
Checks of Kerry's bank accounts and phone have not revealed any activity after 10 June.
Detective Acting Senior Sergeant Jason Poulton from the Homicide Squad said police held grave fears for Kerry's welfare.
"Kerry's disappearance is very much out of character," he said.
"We know he was at the Hells Angels clubhouse in the early hours of 10 June, however what we don't know is what has happened to Kerry and why.
"It's our understanding that Kerry wasn't a patched member and just an associate of the club at the time of his disappearance.
"Investigators believe some kind of dispute has taken place and that may be connected to other members or associates of the Hells Angels OMCG.
"We're appealing for someone who was either there on the night or has knowledge of what happened on the night, to come forward and contact police and this can also be done anonymously.
"Outlaw Motorcycle Gangs are large, complex organisations and not all within the organisation think the same way.
"There will be someone within the Hells Angels OMCG that knows and disagrees with what happened to Kerry, and there is now an opportunity for that person to contact us directly or anonymously.
"Kerry's family are desperate for answers and we're hoping that someone will do the right thing and provide those."
Police have released a photo of Kerry in the hope someone recognises him and can provide information about his movements during his time in Melbourne, particularly on and after 10 June.
They have also released an image of him at a convenience store in South Australia that was captured on the day he left the state.
This image shows him wearing a distinctive Chicago Bulls sweatshirt, which he was known to wear whilst in Melbourne.
Today detectives from the Homicide Squad, Echo Taskforce and Yarra Crime Investigation Unit executed search warrants at three properties, including the clubhouse in Thomastown and residential properties in Richmond and Melbourne.
Anyone with information about Kerry's current whereabouts or his disappearance is urged to contact Crime Stoppers on 1800 333 000 or make a confidential report at www.crimestoppersvic.com.au
